Soviet Tube Coding and Transcription to Latin alphabet

1959 standard coding

Pre-WW2 soviet tube coding consisted of 2 or 3 cyrillic letters followed by 3-digit code. Well before WW2 began, FDR was fueling Joe Stalin, pumping tubes and tube-building machinery by shiploads. In 1939 (according to post-WW2 sources), this new machinery already produced the American tube types under their original names, in such amounts that in the same 1939 the American convention, transcripted to Greek letters, became a codified standard, so far coexisting with indigenous naming convention.

Military hardware received from the U.S. in 1941-45 was equipped mostly with VT-coded tubes. VT-tubes left very scarce traces in Soviet tube annals, just like British tubes. Of course, most of these VT-s were destroyed in action soon upon arrival and never needed maintenance. But I presume the main reason is that civilian American tube codes were a generally accepted standard well before WW2.

Original octal tube codes like 6J5, 6N7 etc. that were reproduced as is in the Soviet Union received names directly transcribed from originals. For simplicity, only one 'middle' letter was left out. The trailing number lost it's 'pin count' designation, becoming simply a serial number. Eventually, the code table was extended to accomodate nearly all new tube types, and as the pre-WW2 designs were retired, became a unified standard (1959). Some older tubes survived until the end of tube era with original non-standard names (i.e. G807). Gas regulators usually follow the 1959 standard, omitting heater voltage code.

In the English-speaking audio world, Soviet single and dual triodes names are frequently written as 6H** or 6C** in Latin letters, which in my opinion is misleading although graphically identical (and accepted by the Chinese :) ). That's why I (like the fellows at Svetlana and many others) use phonetic transcription: triode types are 6n** and 6s**, etc. To separate Soviet and American (and Chinese) tubes with the same Latin names, American originals are written with a #prefix (#6F6, #6SN7).


Although I have data on the tubes coded to pre-WW2 standard, they are not posted on this site... I could but why? Email me in case you found some.

Transmitter/Modulator tube coding

Although a few transmitting tubes were named within 1959 standard framework, most transmitter tubes follow a different name convention that goes back to the 1930-s. These names consist of two or three letters followed by number and a suffix letter:

Suffix stands for: A - Forced Liquid Cooling, B - Forced Air Cooling, no suffix: Convection Cooling.

Data Book Index - T-Files Index - Klausmobile Home - Mail (c) klausmobile 2001

Hosted by uCoz